1. Field of the Invention
The present invention relates to counting the number of steps taken by a walker, and more particularly, to a method and apparatus for counting the number of steps taken by a walker according to a walking pattern of the walker.
2. Description of the Related Art
An apparatus for counting the number of steps measures the number of steps taken by a walker while the walker walks or runs and a distance the walker travels. Such an apparatus counts the number of steps taken by a walker using various methods. For example, the apparatus senses an acceleration value generated by a vertical movement of the body while a walker walks and counts as one step when the acceleration value is higher than a predetermined value. As a second example, a sensor capable of sensing pressure generated by a walker's stepping is included in a walker's shoe. Thus, pressure is applied to the sensor whenever the walker takes a step and the number of steps taken by the walker is counted by calculating the number of times pressure is applied to the sensor.
Some pedometers count steps more directly by means of a sensor or sensors embedded in the shoe that are connected directly to a counter. This can be done mechanically where each step depresses a mechanism that causes a mechanical counter to increment. More frequently electrical means are used whereby an electrical switch is closed by each step, creating an electrical signal that causes an electronic counter to increment. In particular, these pedometers allow the user to change gaits while walking and running.
Another type of pedometers incorporate acceleration sensors. However, they attach to feet or shoes (U.S. Pat. No. 6,145,389), or to a walker's ankles (U.S. Pat. No. 5,485,402). In some cases, the arrangement may increase their accuracy but at cost of inconvenience in the arrangement. U.S. Pat. No. 4,736,312 discloses a device that measures the stride length of a runner by measuring the elapsed time between the time when one foot lifts off the ground and the time when the other foot hits the ground during a stride. The shoes on both feet are equipped with sensors, and the data from both must be communicated to a central processor that performs the distance calculation. Shoe sensors are impractical, since they require special shoe modifications and possibly wires up the leg of the user. Since it is comprised of three different components, a system is also more expensive than a single unit. U.S. Pat. No. 5,485,402 discloses a gait activity monitor that incorporates an accelerometer attached to the ankle of the wearer, which measure the acceleration of the ankle. A data processor processes this acceleration data, counting and recording the number of steps taken during each measurement time interval. It is not a self-contained unit that the user can portably wear. Some pedometers incorporate an accelerometer (U.S. Pat. No. 5,583,776), which is used as a more accurate alternative to the pendulum mechanism, but the system includes a foot-mounted unit, a wrist-mounted unit, and a chest-mounted unit, all attached to a user who is in locomotion. In U.S. Pat. No. 6,611,789, a “foot contact time” of a user in locomotion is measured for monitoring movement, wherein “foot contact time” refers to the period of time that a foot of a user is in contact with the surface during a stride taken by the user while the user is in locomotion on foot.
However, since conventional apparatuses for counting the number of steps do not perform step counting according to such a walking pattern of a walker as walking or running, it cannot accurately count the number of steps taken by the walker. In other words, when the predetermined value is set based on a walker's walking, the number of steps while the walker runs may be counted higher than the number of steps that are actually taken by the walker. When the predetermined value is set based on a walker's running, the number of steps when walking may be counted lower than the number of steps that are actually taken by the walker. In addition, when using the sensor capable of measuring pressure generated by a walker's stepping, other types of pressure as well as pressure applied to a sensor by a walker's stepping are regarded as being generated by a walker's stepping and thus a count value is mistakenly incremented as a step taken by the walker.